Three Dimentional EBSD-based Microstructure Reconstruction And Micro-mechanical For GH4169 Superalloy

The purpose of this paper is to develop computational simulation based on the characterization of microstructure of materials,so as to better understand the relationship between material properties and microstructure.In the past,the study of materials is often limited to the analysis of the surface of materials to infer the overall mechanical properties of materials,but also because the internal microstructure of materials is difficult to be directly observed by instruments,even if it can be directly observed,its depth is extremely limited.The reconstructed polycrystalline microstructure can provide the corresponding materials with the geometric morphological information of their internal microstructure,so as to analyze the properties of the materials more thoroughly and truly.In this paper,a two-dimensional and reconstructed three-dimensional model of GH4169 superalloy based on crystal plasticity is proposed to study the difference between the two-dimensional model and the reconstructed three-dimensional model.When the finite element software is used to simulate the calculation,periodic boundary conditions are given to the model and discretized by finite element method.In this paper,the material parameters of the constitutive model are calibrated based on the experimental data,and a series of subsequent simulation calculations of mechanical properties are carried out according to the parameters.In order to study the difference between the three-dimensional model and the two-dimensional model in the microstructure,a three-dimensional reconstruction technique based on the EBSD experimental data is developed independently to analyze the research object,that is,to obtain the information of each layer of the microstructure by grinding and polishing the studied material.According to the developed MATLAB,the code combines its information to form a model of 3D reconstruction.On this basis,a new single crystal model is built according to the experiment,and the corresponding user subroutines are developed in the finite element software.The mechanical behavior of the single crystal model in different crystal orientations is systematically analyzed and compared with the experimental results by comparing with the experimental data to calibrate the relevant material parameters.Based on the single crystal model,the single crystal model has a certain predictive ability and the mechanical behavior of the polycrystalline model of the same material is predicted,and the correlation between the single crystal and the polycrystalline material is studied.Based on the two-dimensional model and the reconstructed three-dimensional model,a series of mechanical behaviors are simulated and calculated.It is found that the two-dimensional model RVE and the three-dimensional model RVE are not representative in damage simulation,that is,they have size effect.The comparison between the two-dimensional model and the three-dimensional model in damage state proves that the two-dimensional model has limitations.To sum up,the limitations of behavioral simulation and analysis all illustrate the necessity of the study of three-dimensional reconstruction of microstructure.